PCT International Publication WO 2014/016794, whose disclosure is incorporated herein by reference, describes scanning micromirrors, which are based on microelectromechanical systems (MEMS). Embodiments described in this publication provide scanning mirror assemblies that include a support structure; a base (also referred to as a gimbal), which is mounted to rotate about a first axis relative to the support structure; and a mirror, which is mounted to rotate about a second axis relative to the base.
In one of the embodiments described in WO 2014/016794, capacitive sensing is used to monitor the rotation of the mirror, using plates of a capacitive sensor that are positioned in proximity to the mirror on opposite sides of the axis of rotation. In the disclosed embodiment, the plates are angled relative to the plane of the support structure, although in other implementations, the plates may be parallel to the plane of the support structure. Changes in the capacitance between the plates and the mirror are measured so as to monitor rotation of the mirror.